feat(tools): Tools settings category + re-detect for supporter binaries (T-495)

ToolsSettingsExtension adds a Tools settings category — a path field per
tool (app.tools.<name>) plus a Re-detect action (tools.detect) — and keeps
the live resolver in sync as paths are edited (supporterBinariesFrom). en
+ nl catalogs. Completes the D-104 UI surface.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/builtin/tools_settings/extension_test.dart

@@ -0,0 +1,47 @@
+/// T-495: ToolsSettingsExtension contributes the Tools settings category and
+/// the tools.detect command, and keeps the live resolver in sync with edits.
+library;
+
+import 'package:clide/builtin/tools_settings/tools_settings.dart';
+import 'package:clide/extension/extension.dart';
+import 'package:clide/src/env/supporter_binaries.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../helpers/kernel_fixture.dart';
+
+void main() {
+  late KernelFixture f;
+  SupporterBinaries? saved;
+
+  setUp(() async {
+    saved = activeSupporterBinaries;
+    f = await KernelFixture.create();
+    f.services.extensions.register(ToolsSettingsExtension());
+    await f.services.extensions.activate('builtin.tools-settings');
+  });
+  tearDown(() {
+    activeSupporterBinaries = saved; // un-pollute the process-wide resolver
+    f.dispose();
+  });
+
+  test('contributes the Tools settings category and the tools.detect command', () {
+    final ext = ToolsSettingsExtension();
+    final cats = ext.contributions.whereType<SettingsCategoryContribution>();
+    expect(cats.any((c) => c.category.id == 'tools'), isTrue);
+    expect(f.services.commands.get('tools.detect'), isNotNull);
+  });
+
+  test('editing a tool path in settings rebuilds the live resolver', () async {
+    await f.services.settings.set<String>(supporterToolKey('d2'), '/custom/d2');
+    // The listener rebuilt activeSupporterBinaries from the keys; /custom/d2
+    // isn't a real file, so it reads as a stale pin — proving the edit took.
+    expect(activeSupporterBinaries?.isStalePin('d2'), isTrue);
+  });
+
+  test('tools.detect runs, marks first-run done, and refreshes the resolver', () async {
+    final r = await f.services.commands.execute('tools.detect');
+    expect(r.ok, isTrue);
+    expect(f.services.settings.get<bool>('app.tools.detected'), isTrue);
+    expect(activeSupporterBinaries, isNotNull);
+  });
+}